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This is not your father's EQ

AudioControl's FOUR.1i equalizer takes the old-school in-dash EQ to a whole new level. This little problem solver features 4-band equalization, a parametric bass equalizer, and a built-in line driver that'll send a hot, clean signal to your amps.

Find those trouble spots

Mount the FOUR.1i in your vehicle's dash opening along with your receiver, or under the dash if space is an issue. For connections, you'll find a set of inputs, front and rear outputs, and an auxiliary input for an iPod or other audio source. You can adjust response at 125, 500, 2000, and 8000 Hz, then use the parametric EQ to find and kill any bass trouble spots between 40 and 80 Hz.

Set up in an instant

AudioControl makes it easy. Bring up your input knob until its LED starts to flicker, then adjust your output level to get the most out of your amplifiers. You can switch between your main and auxiliary sources with the touch of a button. The ground isolation selector allows you to minimize noise in your system. You can choose between green or amber illumination.

Hands-on research

What's in the box?

Scratch & Dent items may be missing non-essential accessories. In some cases the manufacturer's accessories have been replaced with generic equivalents.

Product Research

Features

Description: The
Four.1i is a combination equalizer/line driver. The 1/2 DIN chassis can be
mounted in-dash, or under-dash using the included brackets.

4 Band
Graphic EQ: The rotary knobs adjust the signal +/-12 dB at 125 Hz, 500
Hz, 2 kHz, and 8 kHz. There's a notch at each knob's center position so it's
easy to return to the flat setting.

Para-Bass: Para-Bass is a
single band, parametric equalizer for the bass output. Like the four graphic EQ
bands, the adjustment range is +/-12 dB; the center frequency is continuously
variable from 40 Hz to 80 Hz.

Line Driver: To achieve the
best possible signal to noise ratio and dynamic range from your amplifier, the
built-in line driver can increase the head unit's output voltage up to 20 dB (9.5 volts RMS/
13 volts peak).

Aux In: In addition to the
main input, there is an auxiliary input (stereo RCA). A switch on the front
panel toggles between the two inputs.

Volume: If you choose, you
can adjust the system volume using the Four.1i's volume knob. This allows you to
leave the source volume at it's maximum un-clipped level, resulting in the best
signal to noise ratio and dynamic range output from the source.

Fader: Because there is
only one stereo line input and both front and rear line outputs, the front panel
fader knob is needed to adjust the relative front and rear volume.

Input Gain: The input gain for the left and right channels
is set independently; 0 dB to +20 dB. The +20 dB gain allows you to increase the
head unit's line voltage to the top of your amp's input range; up to 9.5 volts RMS/13 volts peak.

Balanced
Inputs/Outputs: Using the balanced differential input circuit cancels
noise picked up in the transmission line between the Four.1i the the source
unit, or between the Four.1i and the amplifiers. Both the main and auxiliary
inputs and the outputs can be individually set to balanced or unbalanced, incase
your amps don't accept balanced inputs.

Ground Isolation: The power supply ground is switchable, in case of
ground loop noise. The factory position is fully isolated (typically the best
choice), but can be changed to Ground or 200Ω.

Terminal Block: The
power/ground/remote/illumination terminal is removable; the wiring is attached
to the block, then the block is plugged into the rear panel of the Four.1i.

Illumination: The outer ring of each knob is lit whenever the
illumination terminal is energized. The color is switchable between green and
amber.

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Equalizing the right way!

Written By Anonymous, Kansas on Saturday, February 15, 2014

My bass would fade down as I drove due to change in voltage (or something like that). After installing this I would always get maxium bass, and I could adjust it when I needed that little extra punch on my bass! Before installing this equalizer I was not happy with the constant bass/clarity I was getting from my stock radio with aftermarket speakers and sub. After installing it I am now happy with the way my system sounds! I feel I have completed my system. Would recommend this to everybody that loves to hear music! I had a professional install it.

yep the best eq out there

This EQ is the best.It will totally enhance your system unlike the others out there.As soon as I hooked it up,my system came alive and I dont even have to raise the volume real high to get the benefits.Its worth the money.I was at first skeptical because of the price,but like they say if you want something good you know what you have to do

AudioControl FOUR.1

Written By CREATOR, Calgary AB Canada on Monday, October 12, 2009

PIMP piece- AGAIN! Another product in my SHOW TRUK! Wouldnt be without it! Total control and COOL sweep adjustment finds THE loudest Bass frequency IN UR VEHICLE! Then, the GAIN control? AND the MASTER volume?? OUCH! Hard hitting, tight, hammertime bass. The double octave EQ points, are perfect for those pesky naisly midrage tones! & the 8K adjustment just takes the edge off, off-axis tweets to keep them from peeling off ur eyebrows!

ONE input and it gives u FADER output- WHO else would think of that! CONTROL both ur Bass amps AND ur component power! DO urself a favor and Get ur mitts on one of these NOW!